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cellphone with multiple simcards

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overmind

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hello everybody, i dont know if this is the right place to ask my question. nyway, does anybody have a clue on how cellphones with multiple sim cards work? does it have two engines inside? how can its antenna isolate the two signals for each sim. please help.. thanks..
 

Mikebits

Well-Known Member
hello everybody, i dont know if this is the right place to ask my question. nyway, does anybody have a clue on how cellphones with multiple sim cards work? does it have two engines inside? how can its antenna isolate the two signals for each sim. please help.. thanks..
Why would you want such a thing? This smells nefarious to say the least. Antenna has nothing to do with the Identity module.
 

picbits

Well-Known Member
Usefull if you have a business mobile number and a personal number that you wouldn't want business contacts to get their hands on.
 

vsmGuy

New Member
You can build your own using a DPDT IC and an array of sim card holders. You can control the DPDT via a manual switch or a uC.

SIMs are just a uC with an IMSI in them that separtes one from the other.
 

RCinFLA

Well-Known Member
And with a DPDT switch, how would the phone know which user subscription to service? And then there is the potential subsidy lock issue with many carriers. Phone also has to go through a cold reset (turn-off, turn-on) to bond with a SIM. (SIM card is encrypted) When a SIM card is pulled when phone is on, it will either shut itself off or go to a non-subscription camped state.

The dual sim phone actually has two subscription registrations and examines the PCH (paging channel that sets up ring) for both subscriptions.

The cellphone processing works harder, all things being equal, resulting in less standby time on phone.

This feature is popular in China/Taiwan.
 
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Rolf

Member
hello everybody, i dont know if this is the right place to ask my question. nyway, does anybody have a clue on how cellphones with multiple sim cards work? does it have two engines inside? how can its antenna isolate the two signals for each sim. please help.. thanks..
You can have your phone unlocked (hacked) so that you can use any SIM card you like. But I don't know of any that has two SIM card slots.
 

overmind

New Member
Why would you want such a thing? This smells nefarious to say the least. Antenna has nothing to do with the Identity module.
sir, my apologies if you feel that way but i want to assure you that my intentions are clean. i have a friend that has an I9 iphone clone from china and i am just amazed at this new technology. as a hobbyist, i want to create my own pc-based version. i want to incorporate two mc55 gsm modules and use just one antenna. i want these modules to work at the same time where in they would connect to their own network depending on the sim card that is inserted in its slot. i hope somebody here can help me.. thanks
 

overmind

New Member
You can build your own using a DPDT IC and an array of sim card holders. You can control the DPDT via a manual switch or a uC.

SIMs are just a uC with an IMSI in them that separtes one from the other.
thanks for the reply but this setup would let you use one sim at a time. what i want is that both sims would connect to their network at the same time just like an I9 iphone clone.. any ideas how they are able to do it? thanks
 

georgetwo

Member
a single sim phone can also be converted to dual sim. this can bed done by the application of dual sim pack, you can get this from any good phone engineering shop. in this module, there is a chip which adds the dual sim function to the phone. it works with almost every camera phone. what i want to say is that the entire mobile phone is programed. the case of network identification, eyery network has its own id. and every sim is granted access to only one network. the phone acts an interface.
 
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